RENNES, France, April 13. THE fireworks tonight all occurred in semifinal action as swimmers put up some startling times at French Nationals this evening.

Olympic Nice's Camille Muffat became the first female under 1:56 this year in the women's 200-meter free when she blazed semifinals with a sterling 1:55.69. That bettered the 1:56.51 set by Federica Pellegrini in Italy yesterday that had been the world leader. It also beat the 1:56.55 from Sarah Sjostrom at the Eindhoven Swim Cup last month as well as the 1:56.93 and 1:56.96 put up by Katie Ledecky and Missy Franklin last night at the Arena Grand Prix in Mesa. Muffat could be looking at downing her French record of 1:54.66 during finals.

Mulhouse' Coralie Balmy (1:57.67) and Olympic Nice' Charlotte Bonnet (1:57.70) qualified second and third out of semis, and will provide Muffat's top challenges.

Amiens Metropole's Jeremy Stravius scratched the 200-meter backstroke to focus on his 100-meter fly and 200-meter free this evening and it paid off as he posted a pair of 52s in prelims and semis of the 100 fly. First, he qualified with the top seed out of prelims with a 52.67 before dropping a 52.59 this evening in semis. That puts him within striking distance of Zhou Jiawei's world-leading effort of 52.11 from Chinese Nationals as the second-fastest swimmer in the world so far this year.

Spain's Rafael Munoz Perez qualified second in 52.71, clipping his previous season best of 52.72 from the Spanish Open Championships. Lyon's Romain Sassot (53.39) and Dauphins' Mehdy Metella (53.40) qualified third and fourth out of semis.

With Stravius scratching the 200-meter back this morning, the door is wide open in the event for an additional Worlds qualifier. French-record holder Ben Stasiulis led the way with an easy-speed time of 2:00.90 in semis, while Eric Ress could slide into the open spot after a 2:01.34 in semis. Hungary's David Verraszto (2:02.93) and Mulhouse' Nathan Bonnel (2:03.13) earned the third and fourth seeds.

Yannick Agnel warmed up in the men's 200-meter free semis with a 1:47.28. He has Sun Yang's world-leading 1:44.99 on his mind as Agnel has already clocked a 1:46.11 at the Golden League Circuit meet in Nice in January. Agnel definitely has the ability to turn up the heat and challenge Sun at the top of the world charts. Marseille's Gregory Mallet qualified second in 1:48.38, while Stravius wound up third in 1:48.94.

Nantes' Cloe Credeville opened up the evening with a victorious time of 29.15 in the women's 50-meter backstroke, while Olympic Nice's Beryl Gastaldello touched out Valence's Mathilde Cini, 29.21 to 29.25, for second-place honors in the sprint backstroke event.

Montauban's Coralie Dobral cleared Dauphins' Fanny Deberghes, 2:30.39 to 2:30.70, for the women's 200-meter breaststroke title. Tarbes' Laura Paquit rounded out the podium with a third-place time of 2:31.59.

Hungary's Eszter Dara edged Olympic Nice's Marie Wattel, 59.63 to 59.71, in the women's 100-meter fly finale. Wattel's teammate Beryl Gastaldello checked in with a third-place time of 1:00.04 to round out the podium.